Tropical Storm Dongo
Severe Tropical Storm Dongo (Joint Typhoon Warning Center designation: 06S) was the fifth tropical disturbance and fourth named storm of the 2008–09 South-West Indian Ocean cyclone season. Dongo developed out of an area of low pressure near the remnants of Severe Tropical Cyclone Billy early on January 7. The low was quickly declared a tropical disturbance later that day, and a tropical depression the following day. Shortly after being declared a tropical depression, it was further upgraded to a moderate tropical storm and given the name Dongo. Convection associated with Dongo decreased as it began to exhibit hybrid features. Late on January 10, convection quickly increased and Dongo intensified into a severe tropical storm early the next morning. Upon becoming a severe tropical storm, Dongo reached its peak intensity with winds of 95 km/h (60 mph 10-minute winds). Despite approaching cooler waters, the storm remained a severe tropical storm until transitioning into an extratropical cyclone early on January 12. The extratropical remnants of Dongo persisted for another two days before becoming non-tropical. Meteorological history The origins of Dongo can be traced back to an area of low pressure that formed far from land late on January 7. At 06:00 UTC, the Regional Specialized Meteorological Centre (RSMC) Météo-France designated it as a Zone of Disturbed Weather 1,530 km (950 mi) northeast of Mauritius. However, strong wind shear was expected to inhibit short term development. A few hours later, Météo-France further upgraded the low to a tropical disturbance. At 15:00 UTC, the JTWC issued a Tropical Cyclone Formation Alert. Situated along the edge of a low-mid level ridge, the disturbance tracked towards the southwest. Despite a brief decease in convection, at 06:00 UTC on January 9, Météo-France upgraded the disturbance to a tropical depression. Shortly after, the depression was upgraded to Moderate Tropical Storm Dongo. At the time of the upgrade, Dongo began to turn more towards the south as further development of the storm was anticipated. Roughly three hours later, the JTWC began issuing advisories on Tropical Cyclone 06S . After weakening slightly early on January 10, Dongo began to turn towards the southeast. Subsequently, convection rapidly decreased, leaving the center partially exposed even though conditions were favorable for intensification. Six hours later, however, Dongo intensified into a severe tropical storm while reaching its peak intensity with winds of 95 km/h (60 mph 10-minute winds) with a minimum pressure of 984 hPa (mbar) according to Météo-France. Furthermore, Dongo peak with winds of 100 km/h (65 mph 1-minute winds) according to the JTWC about 1,240 km (770 mi) east-southeast of Mauritius. Tracking towards the south-southeast, Dongo approached cooler waters and began to transition into an extratropical cyclone. Wind shear was also increasing over the storm in response to an approaching upper-level trough. Despite moving over cooler waters, the storm remained a severe tropical storm until being declared extratropical at 06:00 UTC on January 12. Several hours later, the JTWC issued their final advisory on the system Early on January 13, Météo-France followed suit, though it was later believed to have completed such transition earlier. Impact As Dongo remained out over open waters for the duration of its existence, there was no impact on any land-masses. References External links *Joint Typhoon Warning Center (JTWC). *Météo France (RSMC La Réunion). Category:Wikipedia Archives